IPv6 is gone. I took out the HOSTS entries and everything is resolving okay without them now.

I'm still getting the 5305 error, though. Been trying a bunch of different things this morning, my current lead is the lack of an [ENV] entry for EMSMDB32.DLL as listed in KB15779. Still trying to figure out why the 0x80040111 error keeps coming up. I enabled that logging on our domain controllers and didn't find that issue you mentioned earlier, but I do see a trio of NTDS events happening in rapid succession - event 1172 by ANONYMOUS LOGON, a N/A event 2041, and then event 1138 from user besadmin. The IP listed in the 1172 event is the LAN IP of the server. Why would it be using ANONYMOUS LOGON...?